7"!!! Wow. Yeah, that fertilizer app is long gone.

Not sure I agree. A sports field is pretty flat overall. The thing that washes fertilizer away is water running over an area, not water sitting on an area. Granted, 7 inches is a lot of water, but as long as it is going down into the soil and not across, it doesn't necessarily wash granular fertilizers away.

Anyway, there is really only one way to tell. Wait a couple weeks. If the grass gets greener and is growing strong, most of the fertilizer stayed put.

Synthetic ferts being water soluble has much more to do with their propensity to leach than anything else. The nitrates go where the water goes and that much rain can wash out even insoluble nitrogen forms. Its gone.

Except most synthetic fertilizers are designed not to be water soluble. They are blended with binders that keep them from dissolving so that they will be "slow release." If the individual granules aren't washed away, the nutrients aren't either.

But I think she's more concerned about the grub control.

Would the grub chemicals survive that much rain. Would it just wash thru the soil and not affect the grubs?

Capt Tom

I agree with captaintom, if the "scotts technology" grub control product was imidacloprid (which sounds likely, since Scotts uses it, even if Bayer actually developed it...), that stuff binds with the soil and persists for a few months, much longer than urea nitrogen. So I think it is possible that most of the fert has run off or leached out, but the grub control, though applied a little early, should mostly still be there, and very, very well watered in ;-).

I'll confess Im not familiar with Anderson's product and the lawn guy claiming that its the science behind Scotts doesn't put a very fine point on it after all. And Im not familair with any product that makes any kinds of efficacy claim after that kind of rain. All those qualifiers aside I do think its more likely the grub treatment will be present in the soil to one degree or another.

Ask the applicator about the label. If it includes warnings about applying close to water then you're probably good in a backwards kind of way.

All right, we all agree: we don't know.

Yes, 7" of rain is a lot. But yes, if there's not a channel, that will look like a river, with 7" of rain, but won't look like a river with a lot less rain, then I have to tell you that I'm absolutely positively sure, that "it depends". .

You mighta got lucky. You mighta not got lucky. You really have to just wait.

But there's more: you should ask an attorney, or an insurance expert, to look at your insurance policy for that property/owner. 7" of rain is an insurable event, and may well not be excluded by an exclusion for 'flood'....nothing floated away. I don't want to quibble about this, here in the forum, but I'm suggesting that an expert be consulted.

Well, you said it yourself, "...and much runoff into the drainage ditches". I agree with most others that waiting for a while to see what happens is probably prudent, but with that much rain AND runoff I find it hard to believe that a least some if not most of the applications should be reapplied...but then I'm not a professional and can't see your field, so getting a professional opinion/ruling should be done.

Thank you all for your input. Last night we had tornados and another 2" of rain, on top of what we already had. Much of the field area is now underwater again.

As far as drainage ditches, these are not ditches as usually thought of, but rather just depressions that are probably 2 feet deep and 4 or so feet wide. So there isn't really all that much water that runs fast towards them.

I tend to agree with you-all, we'll just have to wait and see. And I have a feeling that this year, the water standing will do way more damage than grubs ever thought of doing. And maybe the grubs all drowned. :0)

Assuming it was a slow-release fertiliser, and the release mechanism is based on temperature rather than moisture, you will be fine as long as the fertiliser granules are still there.

If the grub control is imidacloprid based, you will be fine. Once absorbed, imidacloprid offers systemic pest control, and therefore is not in danger of being 'washed off'. Imidacloprid is used extensively in lettuce crops. As a seedling, lettuce is flooded with imidacloprid solution prior to planting. Once planted, many inches are applied during the first week to settle the plant in. Imidacloprid retains its pest-control characteristics under this situation, so I would guess it would in this situation.

One possible "silver lining" in all of your recent clouds is that the extra two inches of rain that you just got was probably absorbed fairly easily by your soil. Water will run off of a dry sponge, but sink right into a wet one. Soil behaves the same way. Given your previous rains your soil was wet, and if it is not clay was ready to absorb at least most of it.

That said, I think most of your fert may be gone (assuming that much of it was fast-release), but also assuming the grass plants had sufficient time to take the (presumed) imidacloprid into their roots, your grubs that will hatch in the next two months or so are likely to die. Or at least should be so weakened that they won't cause much trouble anyway. That stuff works by getting into the plant, and then poisoning the grubs when they try to eat the roots. It lingers in the plants for a long time.

Good luck!
Paul

I don't think I am ever eating lettuce again! Yuck!

Dannie, then you can't eat Soy either. That product is a major part of virtually every processed food we eat. Look up "roundup ready," and "soy" and see how much of that stuff (meaning roundup) we are eating. Nauseating! Most notably for the vegans, who are eating most of it, but we don't hear too much about this problem from them...

In my life I have never met a vegan that didn't shop almost exclusively organic so I doubt many vegans are chomping on RU. Just ask one....if you've got plenty of time on your hands.